(a) Field of the Invention
This invention relates to improvements of an exothermic composition for warming bags warming a human body by using as a heat source a compound of a metal powder generating heat in the presence of water and oxygen and a warming bag containing the same.
(b) Description of the Prior Art
There is already known a warming bag wherein a composition prepared by adding an aqueous solution of a salt of a metallic halide (such as NaCl, KCl, CaCl.sub.2, FeCl.sub.3, FeCl.sub.2, MgCl.sub.2, or AlCl.sub.3) or a metallic sulfate (such as Na.sub.2 SO.sub.4, K.sub.2 SO.sub.4, Fe(SO.sub.4).sub.3, FeSO.sub.4 or MgSO.sub.4) to a mixture of active carbon with an exothermic metal (such as an iron powder or the like) is contained in a single bag so as to generate heat by the introduction of air. However, when such exothermic composition is left as insulated all from air, hydrogen will be generated gradually and continuously, will accumulate in the bag, will become high in the concentration with the lapse of days, will inflate the bag occasionally and will have a danger of ingnition and explosion during the preservation. The merchandised conventional warming bag is mostly of such structure that an exothermic metal and a reaction assistant are contained as separately sectioned from each other in a ventilative inner bag which is enclosed with a nonventilative outer bag. When it is to be used, the outer bag will have to be broken and the inner bag taken out will have to be shaken and kneaded to mix the contents much to the trouble. In case the mixing is insufficient, the heat generation lasting time will be reduced and the iron powder will become like a block and will give a different feeling. The charging structure is so complicated that the production rate can not be increased and the cost is high. There are such defects.